The great 8th century linear earthwork known as Offa's Dyke is one of Britain's most remarkable ancient monuments. In places still acting as the border between England and Wales, the massive bank and ditch survives today as a potent symbol of the ancient origins of both nations. Given this received historical importance, it may come as something of a surprise that David Hill's and Margaret Worthington's 'Offa's Dyke: History and Guide' is the first major book on the subject since Sir Cyril Fox's classic 1955 'Offa's Dyke' monograph.

Left: The location of Offa's Dyke as generally recognised. Note the discontinous character of the monument south of Powys, with isolated sections in Herefordshire and Gloucestershire.

Hill and Worthington seem determined to strike a suitably revisionist tone after such a time gap. For a start, they peremptorily reject the traditional 'sea to sea' view of the extent of the monument. They suggest that, in fact, only the 64 miles of more or less unbroken earthwork in the central Marches (Shropshire, Powys, Wrexham and southern Flintshire) is really Offa's Dyke proper, with other isolated sections to be re-interpreted as distinct and unrelated structures. Indeed, there is something of a reforming zeal in their keenness to cut away what are seen as the recent erroneous inventions of Fox and others to leave only the purity of what 'the evidence' and, in their analysis, longer historical tradition really supports. 'The evidence' concerned - mostly derived from Hill and Worthington's own 30 years of excavation and survey - is set out as the pivotal chapter of the book, interspersed with a description of the course of the 'main' dyke.

With their 'short view' of the dyke uncritically accepted as a pre-supposed fact, Hill and Worthington set out a no less definitive explanation of its purpose. They argue that the dyke was built as a defensible (if not heavily defended) earthwork specifically erected by Offa's Mercia against a belligerent 8th century kingdom of Powys. The authors even suggest how the dyke might have 'worked' in this way, with associated chains of beacons, fortified settlements and mobile patrols all looking eminently plausible in the elegant storyboard style narrative drawings which anchor the 'How and Why' explanatory chapter.

The confident clarity of these findings does engender some degree of initial tolerance of the book's superficial shortcomings. So, at first, it seems forgivable that the volume is never really either the 'history' or 'guide' of the subtitle (the story of the dyke beyond the 8th century is dealt with only briefly and by default in the 'Early studies of Offa's Dyke' chapter, and the book would be of little use as a practical field guide). Perhaps too the understanding reader will accept the rather uneasy mixing of academic and popular strands which presumably explains, amongst other curiosities, the seemingly irrelevant 8 page digression on the Anglo-Saxon agricultural year in the 'Background to Offa's Reign' chapter, and the absence of any kind of bibliography or reading list. And even if parts of the text are re-used largely verbatim from some of Hill's earlier articles, then at least the arguments accordingly come with the comfort of rehearsed familiarity.

Yet it gradually gets rather harder to similarly excuse what appear to be much more significant errors and omissions. To take a typical example, Offa's Dyke 'proper' is presented by Hill and Worthington as a uniformly designed structure always having a western ditch (e.g. see 'The Evidence' pg 101), and is unerringly shown as such on the accompanying maps. Yet there are significant sections of the dyke in Radnorshire and south Shropshire where the surviving earthwork clearly appears to have an eastern ditch. Whatever explanatory significance may or may not be attached to such patterns, it is mystifying that this sort of basic detail is entirely overlooked. This is especially so when the existing Offa's Dyke explanations Hill and Worthington dismiss - such as Fox's negotiated frontier hypothesis - stemmed from observation of precisely this kind of localised variation in the form of the earthwork.

Left: Offa's Dyke, Hawthorn Hill, Powys looking north. The low bank with clearly defined eastern ditch follows a sinuous course along the hilltop and seems markedly different in form from nearby western ditched dyke sections.

Once the confident rhetoric of factual discovery is pierced, the whole edifice begins to look rather shaky. Take the case of what, for Hill and Worthington, is the 'rogue' section of Offa's Dyke in Gloucestershire, pre-judged from the outset in this book by its inclusion in the final 'Other Earthworks' chapter. According to Hill and Worthington, the naming of this section as 'Offa's Dyke' is a recent phenomenon - yet an early 14th century reference to 'Offediche' in the area is well documented (VCH Gloucestershire Vol 5, pg 249). More fundamentally, their damning characterisation of this length as no more than slight and intermittent 'supposed earthworks' (pg 146) with 'little similarity to the form or siting of Offa's Dyke in the undisputed central area' (pg 148) bears scant relation to the often massive, mostly continuous and generally impressive earthwork which anyone who visits Offa's Dyke in Gloucestershire will actually find on the ground.

Right: Offa's Dyke, Lippet's Grove, Gloucestershire looking south. The walkers are following the western ditch of the dyke with the massive bank to the left of the picture. To characterise such a substantial structure as no more than 'supposed earthworks' is misleading. It is also woth noting that a nearby length is referred to as 'Offediche' in a 14th century document.

There are significant difficulties here, not just in consistency of descriptive treatment but also of analytical circumspection. The attempt to quote the Gloucestershire Archaeology Service's detailed field survey of the mid 1990s to establish the distinct nature of the Wye Valley earthworks completely ignores the fact that Hill and Worthington's description of the rest of the monument does not follow a comparable frame of reference. There is nothing especially anomalous about the low and eastern ditched sections of Offa's Dyke on St Briavel's Common, Gloucestershire (see pg 146) if the similar sections on Hawthorn Hill (Powys) or Panpunton Hill (Shropshire) are also correctly described in the same terms.

Ultimately, the important and lasting discoveries and insights which Hill and Worthington's excavation work has demonstrably made - such as their identification in the north of the Whitford Dyke as an earthwork separate from Offa's Dyke (pg 154-161) or their contribution to understanding the internal structure and constructional character of localised parts of the monument (e.g, see discussion of gateways and marking out banks pg 87-97) - are not, at the next level, enough to support the grand 'we've solved Offa's Dyke in entirety' claim they seem to be straining to promote. Perhaps placing too much belief in the assumed cumulative value of their numerous small scale excavations, they lose consistency of balanced overview at the wider scale of interpretative synthesis. Moreover, the irony is that Hill and Worthington consequently lay themselves open to much the same critique as they aggressively level at Fox, namely that of allowing a priori preconceptions to influence 'primary' description of the data. In truth, it is Hill and Worthington who probably emerge as the more guilty parties in this respect.

Left: Partial archaeological excavation of the buried ditch of Offa's Dyke, Johnstown, Wrexham. Though such work provides much useful information, there are limits to the interpretative value of this kind of small scale investigation in understanding a physically and geographically massive monument.

From an academic perspective, perhaps the greatest disappointment of this book is the restricted view of the potential of archaeology Hill and Worthington implicitly espouse. Their explanation of Offa's Dyke, and the analytical route by which they get to it, casts the monument as little more than a footnote to the extremely scanty historical sources available for this period. The fact that their 'defensible' dyke model is, by their own
admission, speculation entirely unsupported by archaeological evidence, is presented as a necessary concession to extracting any story at all from a 'dead' structure such as Offa's Dyke (see pg 126). Yet this need to resort to unashamed make believe is surely more a self-inflicted consequence of their own analytical approach. Their attempt to make a critical virtue of simplifying the dyke and its form - by radical pruning of its geographical extent to get rid of the 'problem' of the gaps, by emphasising generalised description which sometimes seems to overlook conflicting evidence, and by virtually ignoring Offa's Dyke's comparative relationship to other nominally similar earthworks such as the nearby Wat's Dyke - only really succeeds in erasing exactly the kind of contextual details and contrasts from which more sophisticated and substantive archaeological explanation could have grown.

This book is important as a summation of Hill and Worthington's excavation work (much of which is not fully published or easily accessible elsewhere) and will, as a long overdue modern overview of Offa's Dyke, certainly help to introduce this remarkable monument to a wider audience. Unfortunately, the overstretched presentation of ideas and interpretations as proven facts will very likely mislead most of those readers. In the end, it is hard to avoid the observation that Hill and Worthington leave Offa's Dyke all too firmly in the Dark Ages.